Instruments and their salient characteristics
1. Theodolite: Angular measurement with the help of vernier scale; both horizontal and vertical angles are taken; helps in the measurement of the height of high-altitude mountains.
2. Clinometers: A handy instrument used for the measurement of the height of the buildings and similar low altitude heights.
3. Dumphy level: Helpful in the determination of spot height
4. Pantograph, Echograph (for smaller area) and Camera Lucida: Used for enlargement and the reduction of the area.
5. Planimeter: Area determination
6. Barometer: Air pressure measurement
7. Aneroid meter: Air pressure measurement; this instrument does not contain mercury
8. Barograph: Air pressure measurement
9. Anemometer: Wind velocity measurement
10. Dry and wet bulb thermometer: Relative humidity
11. Ran gauge: Rainfall measurement
12. Chain: Used for horizontal measurement
13. Tape: Used for short distance measurement
14.Ranging rod: Helps in locating objects
15. Optical square: Used for setting right angles for the measurement of short distance from the chain
16.Spirit level: Used for levelling of instruments
17. Trough compass: Magnetic north is directed
18. Guntur’s chain: A chain having length of 66 feet or 20 metres
19. Engineer’s chain: A chain having length of 100 feet or 30 metres
20. Steel tape or Invar tape: Used for the measurement of base line in geodetic survey or a survey considering the curvature of the earth
21. Prismatic compass: Used for closed traverse survey; angular recording is taken from magnetic north
22.Plane table: An instrument used for detailed survey; entire work is completed in the field
23. Alidade: A sighting rule used with plain table for the alignment of the objects
24. Pluviograph: Rainfall measurement instrument, better than rain gauge
25. Wind vane: Wind direction is indicated
26. Anemograph: Wind velocity measurement
27. Hygrograph: Relative humidity measurement; better than dry and wet bulb thermometer
28. Levelling staff: Used with Dumphy Level, gives reading up to 100th part of a metre or foot for showing ups and downs
29. Plumb bob: Used for the centering of the instrument
30. Opisometer: Measurement of distance on a map
31. Nanometer: Pressure measurement
32. Pyrometer: Measurement of invisible as well as indirect radiation
33. Sextant: Measurement of altitude, mostly used in navigation
34. Cyanometer: Measurement of blueness of the sky
35. Actinometer: Measurement of radiation
Lines in geographical map
1. Isohypes: Lines of equal elevation or contours
2. Isogons: Lines of equal magnetic declinations
3. Isohyets: Lines joining points of equal rainfall
4. Isobath: Lines of equal depth below the sea level
5. Isoneph: Lines of equal cloudiness
6. Isoniph: Lines of equal snow
7. Isorymes: Lines of equal frost
8. Isophene: Lines of equal seasonal phenomenon, like flowering dates of plants
9. Isodapan: Lines of equal transportation cost distance
10. Isleabars: Lines of equal pressure difference
11. Isocline: Lines of equal slop
12. Isobronts: Lines showing places having thunderstorms at the same time
13. Isochromes: Lines of equal wind factor
14. Isochrones: Lines showing places located at equal travel time from a point
Graphs of geography
1. Climograph: It shows variation of mean monthly temperature and relative humidity of over a period of a year for any weather station
2. Hydrograph: It shows the relationship between stream discharge and precipitation at a place
3. Ergograph: It shows the relationship between climate and the growing season of crops
4. Hythergraph: It shows temperature and rainfall at a particular station
5. Windrose: It shows the frequency and directions of winds at a particular place.
(Based on my notes of Prof RB Singh's lecture)
